1. Field of the Invention
The present invention relates to a steering apparatus including a tilt/telescopic adjustment mechanism, with which a firm clamping condition can be maintained during tilt/telescopic adjustment such that rattling throughout the entire apparatus can be prevented.
2. Description of the Related Art
Various steering apparatuses having a tilt/telescopic function exist. One of these apparatuses is a steering apparatus disclosed in Japanese Patent Application Publication No. 2005-47487. The steering apparatus disclosed in Japanese Patent Application Publication No. 2005-47487 will be described briefly below. Note that reference symbols used in Japanese Patent Application Publication No. 2005-47487 are used here as is. An outer column 21 includes a cylindrical portion 21a, and a pair of flange portions 21c, 21d disposed discretely in an axial direction on a vehicle body rear side outer periphery of the cylindrical portion 21a (see FIG. 2 of Japanese Patent Application Publication No. 2005-47487).
An inner column 11 is held so as to be enveloped by the cylindrical portion 21a. A telescopic groove 11a is formed parallel to an axis on either side of the inner column 11 (see FIG. 1 of Japanese Patent Application Publication No. 2005-47487). A tension member 13 is disposed between the flange portions 21c, 21d serving as pressing portions. An upper-lower pair of slits 21e, 21e are formed in the cylindrical portion 21a from a vehicle body rear side end portion so as to divide the flange portions 21c, 21d.
A maximum width of the tension member 13 is smaller than a maximum width of the outer jacket 21. Right half portion and left half portion inner peripheral surfaces of the flange portion 21d of the outer jacket 21 are shaped such that when the flange portion 21d contacts an outer peripheral surface of the inner column 11, gaps are formed in a right side face and a left side face. In other words, the right half portion and left half portion inner peripheral surfaces of the flange portion 21d respectively include recessed portions 21g (see FIG. 4A of Japanese Patent Application Publication No. 2005-47487).
The recessed portion 21g is divided vertically into two by a horizontal line passing through the axis of the inner column 11, and is substantially line-symmetrical about the horizontal line. An inner peripheral surface of the flange portion 21c includes similar recessed portions. When an operating lever L is rotated in a clamping direction, a pressing force is exerted on the respective outer peripheral surfaces of the flange portions 21c, 21d of the outer jacket 21 by bracket portions 12a.
When the outer jacket 21 is pressed from both sides, the slits 21e deform so as to close, causing an inner diameter of the outer jacket 21 to decrease so as to hold the inner column 11. When the two bracket portions 12a press the outer jacket 21 by a force F, the outer jacket 21 contacts the inner column 11 at boundary points X on respective circumferential direction ends of the recessed portions 21g of the flange portion 21d (21c) (see FIG. 4B).
A force F1 for pressing the inner column 11 is generated at the boundary points X. Here, the force F is oriented in a horizontal direction, whereas the force F1 is inclined relative to the horizontal direction by an angle θ. Therefore, the inner column 11 is supported in the horizontal direction by a force of (2×F1 cos θ) and supported in a vertical direction by a force of (2×F1 sin θ).
Hence, in Japanese Patent Application Publication No. 2005-47487, by providing the recessed portions 21g, the inner column 11 can be supported likewise in the vertical direction by a component force of the force F1 generated at the boundary points X, and therefore the inner column 11 can be supported reliably in both the vertical and the horizontal directions.